1. Technical Field
The invention generally relates to driving apparatuses and driving methods of display devices, and more particularly to a driving apparatus and a driving method of a backlight module.
2. Description of the Related Art
In regard to a non-emissive display device such as a liquid crystal display, a backlight module is a main light source of the non-emissive display device. The luminescence characteristic and life-span of the light source generally have in-close relationship with the display quality and life-span of an end product. In order to meet the increasing demands for environmental protection, energy saving, colors as well as images, light emitting diodes have been widely used as such light source.
Nowadays, the backlight module primarily have two operation modes. One of the operation modes is that a plurality of light emitting diodes of the backlight module always keep at on-state, and the other one of the operation modes is that a plurality of light emitting diodes of the backlight module use local dimming technology and thus bright and dark levels of the light emitting diodes in each local area would vary along with the change of panel display signals among bright level, dark level, and gray levels.
When the backlight module is in operation, energy received by the light emitting diodes of the backlight module would be converted into heat except a part thereof being converted into emission light. Since the luminescence characteristic of the light emitting diodes is highly sensitive to temperature, rise in temperature associated with the light emitting diodes would result in brightness decay and emission wavelength shift; and moreover the light emitting diodes would occur the phenomenon of brightness and color decay resulting from aging caused by the use of long-time. As a result, brightness and color of the backlight module in operation would be decayed. Accordingly, how to compensate the brightness and color decay caused by rise in temperature and/or aging of the light emitting diodes, so as to maintain the brightness and color of the backlight module is an issue required to be urgently solved.